Synthesis, X-ray molecular structure, biological evaluation and molecular docking studies of some N4-benzyl substituted 5-nitroisatin-3-thiosemicarbazones.

ABSTRACT

A series of fifteen N4-benzyl substituted 5-nitroisatin-3-thiosemicarbazones 5a-o was synthesized and evaluated for urease inhibitory, phytotoxic and cytotoxic influences. All the compounds proved to be highly potent inhibitors of the enzyme, showing inhibitory activity (IC50=0.87±0.25-8.09±0.23µM) much better than the reference inhibitor, thiourea (IC50=22.3±1.12µM) and may thus act as persuasive leads for further studies. In phytotoxicity assay, twelve out of fifteen thiosemicarbazones tested i.e. 5a-e, 5g, 5i and 5k-o appeared to be active, exhibiting weak or non-significant (5-35%) growth inhibition at the highest tested concentrations (1000 or 500µg/mL). In contrast, only one compound i.e. 5i was active in the brine shrimp (Artemia salina) lethality bioassay, demonstrating cytotoxic activity with LD50 value 2.55×10-5M. Molecular docking studies of compounds 5a-o were also performed to identify their probable binding modes in the active site of the enzyme.